The time-dependent problem in the Jordan-Brans-Dicke tensor-scalar theory of gravitation

Astrophysics ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 288-296
Author(s):  
G. G. Arutyunyan ◽  
V. V. Papoyan ◽  
V. N. Pervushin ◽  
M. B. Sheftel'
Keyword(s):  
Time Dependent ◽  
Scalar Theory ◽  
Theory Of Gravitation ◽  
Time Dependent Problem

scholarly journals Thermomechanical coupling of ice flow with the bedrock

2003 ◽  
Vol 37 ◽  
pp. 390-396 ◽  
Author(s):  
Richard C.A. Hindmarsh
Keyword(s):  
Temperature Distribution ◽  
Horizontal Velocity ◽  
Time Dependent ◽  
Thermomechanical Coupling ◽  
Positive Anomaly ◽  
Thermal Coupling ◽  
Steady Temperature ◽  
Ice Flow ◽  
Time Dependent Problem ◽  
Geomorphological Processes

AbstractTwo aspects of thermal coupling with bedrock are considered: the coupled time-dependent problem of co-evolving temperatures in lithosphere and ice; and the influence of basal topography on steady temperature distribution within the ice. The nature of the time-dependent coupling is found to depend on the horizontal velocity. As has been suggested, there is a cooling of steady temperatures on bedrock highs, but this is phase-shifted downstream when horizontal velocities increase. This observation may have consequences for geomorphological processes such as plucking and protection. The effect of bedrock channelling on steady temperature is considered. The positive anomaly of basal temperature due to channelling increases as the transverse wavelength decreases, but not monotonically, reaching a plateau when both the wavelengths of the basal topography are around 100 km.

scholarly journals The Large Number Hypothesis and Einstein's Theory of Gravitation

1985 ◽  
Vol 38 (4) ◽  
pp. 547 ◽  
Author(s):  
Yun-Kau Lau
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Matter Density ◽  
Time Dependent ◽  
Field Equations ◽  
Large Number Hypothesis ◽  
Theory Of Gravitation ◽  
The Mean ◽  
Limiting Case ◽  
The Universe

In an attempt to reconcile the large number hypothesis (LNH) with Einstein's theory of gravitation, a tentative generalization of Einstein's field equations with time-dependent cosmological and gravitational constants is proposed. A cosmological model consistent with the LNH is deduced. The coupling formula of the cosmological constant with matter is found, and as a consequence, the time-dependent formulae of the cosmological constant and the mean matter density of the Universe at the present epoch are then found. Einstein's theory of gravitation, whether with a zero or nonzero cosmological constant, becomes a limiting case of the new generalized field equations after the early epoch.

scholarly journals hp-FEM for the fractional heat equation

2020 ◽  
Author(s):  
Jens Markus Melenk ◽  
Alexander Rieder
Keyword(s):  
Finite Elements ◽  
Heat Equation ◽  
Exponential Convergence ◽  
Time Dependent ◽  
Nonlocal Operator ◽  
Time Stepping ◽  
Fractional Heat Equation ◽  
Time Dependent Problem ◽  
Hp Finite Elements ◽  
Abstract Framework

Abstract We consider a time-dependent problem generated by a nonlocal operator in space. Applying for the spatial discretization a scheme based on $hp$-finite elements and a Caffarelli–Silvestre extension we obtain a semidiscrete semigroup. The discretization in time is carried out by using $hp$-discontinuous Galerkin based time stepping. We prove exponential convergence for such a method in an abstract framework for the discretization in the spatial domain $\varOmega $.

scholarly journals Thermal ignition in a reactive slab with unsymmetric boundary temperatures

1983 ◽  
Vol 24 (3) ◽  
pp. 279-288 ◽  
Author(s):  
K. K. Tam ◽  
P. B. Chapman
Keyword(s):  
Steady State ◽  
Critical Role ◽  
Upper And Lower Solutions ◽  
Lower Solution ◽  
Time Dependent ◽  
Thermal Ignition ◽  
Time Dependent Problem ◽  
Steady State Solutions

AbstractThe problem of thermal ignition in a reactive slab with unsymmetric temperatures equal to 0 and T is considered. Steady state upper and lower solutions are constructed. It is found that T plays a critical role. Results similar to the case with symmetric boundary temperatures are expected when T is small. When T is sufficiently large, there is only one steady state upper or lower solution. The time dependent problem is then considered. Phenomena suggested by studying the upper and lower steady state solutions are confirmed.

On the Scalar Theory of Gravitation

1965 ◽  
Vol 33 (2) ◽  
pp. 162-163
Author(s):  
A. L. Harvey
Keyword(s):  
Scalar Theory ◽  
Theory Of Gravitation

GLOBAL EXISTENCE AND ASYMPTOTIC BEHAVIOR FOR A SEMICONDUCTOR DRIFT-DIFFUSION-POISSON MODEL

2008 ◽  
Vol 18 (03) ◽  
pp. 443-487 ◽  
Author(s):  
HAO WU ◽  
PETER A. MARKOWICH ◽  
SONGMU ZHENG
Keyword(s):  
Global Existence ◽  
Existence And Uniqueness ◽  
Poisson Model ◽  
Stationary Problem ◽  
Time Dependent ◽  
Unique Equilibrium ◽  
Poisson System ◽  
Drift Diffusion ◽  
Global Existence And Uniqueness ◽  
Time Dependent Problem

In this paper a time-dependent as well as a stationary drift-diffusion-Poisson system for semiconductors are studied. Global existence and uniqueness of weak solution of the time-dependent problem are proven and we also prove the existence and uniqueness of the steady state. It is shown that as time tends to infinity, the solution of the time-dependent problem will converge to a unique equilibrium. Due to the presence of recombination-generation rate R in our drift-diffusion-Poisson model, the work of this paper in some sense extends the results in the previous literature (on both time-dependent problem and stationary problem).

scholarly journals On the Hartree-Fock time-dependent problem

1976 ◽  
Vol 49 (1) ◽  
pp. 25-33 ◽  
Author(s):  
A. Bove ◽  
G. Da Prato ◽  
G. Fano
Keyword(s):  
Time Dependent ◽  
Hartree Fock ◽  
Time Dependent Problem

scholarly journals Design and Analysis of Parison Blow Molding Using Adaptive Mesh

2021 ◽  
Vol 9 (VII) ◽  
pp. 1945-1950
Author(s):  
Syed Ayesha Yasmeen
Keyword(s):  
Transient Flow ◽  
Thickness Distribution ◽  
Numerical Data ◽  
Adaptive Mesh ◽  
Time Dependent ◽  
Molding Process ◽  
Pet Bottles ◽  
Blow Molding ◽  
Time Dependent Problem ◽  
Stretch Blow Molding

Blow Molding is one of the most versatile and economical process available for molding hollow materials. When polyethylene is stretched, it exhibits strain-hardening properties, which are temperature, pressure, velocity and strain-rate dependent. In this paper, preform is made by extrusion and forced between two halves by pressurization. This process includes isothermal and transient flow of Newtonian fluid in complex geometries simultaneous with structuring and solidification. A time dependent problem is defined and setting material properties and boundaries condition for bottle blow molding. Numerical data available in POLYDATA for a time dependent problem using ANSYS POLYFLOW were applied. Results display in form contours associated with different variables at different time steps and good agreement with the bottle thickness profile is observed. In this paper, the analysis of the stretch-blow molding (SBM) process of polyethylene terephthalate (PET), parison plastic bottles is studied by the finite element method (FEM). A hyper elastic constitutive behavior was calibrated using material data available in literature in variant high temperatures and strain rates and was used in the numerical simulation. Hydrostatic pressure with convention heat transfer has been used instead of a blowing process. Comparisons of numerical results with experimental observations demonstrate that the model can predict an overall trend of thickness distribution. Through the study, it becomes clear that the proposed model is applicable for simulating the stretch-blow molding process of PET bottles, and is capable of offering helpful knowledge in the production of bottles and the design of an optimum preform.

scholarly journals Dynamics of logarithmic negativity and mutual information in smooth quenches

2020 ◽  
Vol 2020 (7) ◽  
Author(s):  
Hiroyuki Fujita ◽  
Mitsuhiro Nishida ◽  
Masahiro Nozaki ◽  
Yuji Sugimoto
Keyword(s):  
Mutual Information ◽  
Time Evolution ◽  
Qualitative Difference ◽  
Time Dependent ◽  
Late Time ◽  
Finite Mass ◽  
Scalar Theory ◽  
Quasi Particle ◽  
Logarithmic Negativity ◽  
Free Scalar

Abstract We study the time evolution of mutual information (MI) and logarithmic negativity (LN) in two-dimensional free scalar theory with two kinds of time-dependent masses: one time evolves continuously from non-zero mass to zero; the other time evolves continuously from finite mass to finite mass, but becomes massless once during the time evolution. We call the former protocol ECP, and the latter protocol CCP. Through numerical computation, we find that the time evolution of MI and LN in ECP follows a quasi-particle picture except for their late-time evolution, whereas that in CCP oscillates. Moreover, we find a qualitative difference between MI and LN which has not been known so far: MI in ECP depends on the slowly moving modes, but LN does not.

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